so this presentation includes breeding and seed production of both edible and pearl oyster, which are basically same in a way. note that this does not includes pearl formation in the pearl oyster but after reading this presentation you might learn how to the culture the oyster. good luck! and have fun.

1. SEED PRODUCTION AND BREEDING OF
PEARL OYSTER &EDIBLE
OYSTER
By: Abhay Bamaniya

2. INTRODUCTION
Culture of molluscans were done even from the era of Romans.
Bivalves such as oysters, mussels, clams, scallops and a few other
gastropods such as abalones, top shells are extensively cultured in
mainly in subtropical and temperate countries such as USA, Japan,
Korea, France, Spain, Netherlands, Italy etc.
Till recent years seed for culture was obtained through collection of
spat from natural spawning grounds.
during recent years technology has been developed for the seed
production of these organisms in controlled conditions and hundreds
of commercial hatcheries have been established in several countries.
These hatcheries not only cater to seed requirement of the farms but
also provide seed for stock enhancement through ranching the
natural water bodies

4. Al oysters are protandrous hermaphrodites, being males first and later changing female.
In Crassostrea change of sex takes place between spawning seasons but in To Ostrea it may
take place in the same season.
In Crassostrea males and females release gametes in to the water where fertilization
takes place.
But in flat oysters males release sperms in to the water which enters in to the pallial
cavity of female along with the inhalent water and fertilization takes place in the pallial
cavity. The zygote undergoes development for 8-10 days and when it reaches the veliger
stage which escapes out. Rest of the development takes place in the water.
• The flesh is encased by two shell valves
• The lower valve is cemented to the substratum and the upper valve acts as a lid.
• The hinge mechanism connecting both valves, allows the valve to open or close
• The animal feeds by filtering the microscopic organisms in the water which pass
through the gap between the two valves⁃ The flesh of oyster is highly nutritious
containing 8-10% protein and 2% fat, in addition to minerals like calcium, phosphorus,
zinc, iodine.

5. EDIBLE OYSTER
• Cultivated oysters belong to two genera such as Crassostrea (cupped oysters) and
Ostrea (flat Oysters).
• Are called as true oysters(ostreidae)
• Edible oysters are cultured extensively in several European countries, America and
some tropical countries as it is highly relished as a delicacy. C.gigas served on half
shell fetches very high price.
• species of Crassostrea of global importance are:
• C.virgiica (American oyster),
• C.angulata (Portugese oyster),
• C.commercialis (Sydney rock oyster),
• C.glomerata (Auckland rock oyster),
• C.plicatula(Chinese oyster).
• In India C.madrasensis is the common species found.
• Common species of Ostrea are:
• Ostrea edulis (European oysters) and O. lurida (Olympian oysters).

6. Temperature
o
C 23- 34
Salinity (ppt) 10 to 38
pH 6.5 – 8.5
Edible oysters occur attached to hard substrata in the intertidal
areas, backwaters, muddy bays, lagoons, and creeks along the east
and west coasts of India
Dissolved oxygen mg/l 3–5

7. REPRODUCTIVE BIOLOGY
• oysters do not exhibit external sexual
dimorphism
• All oysters start life as male, but most
will change permanently to female after
about a year.
• Oysters spawn throughout the year with2
peak periods in April-May and August-
September. The peak period varies from
place to place, depending on
environmental factors.
• The larvae are pelagic. When the larvae
attain pediveliger stage, they begin to
crawl with the help of foot and settle on
suitable substratum.
• This process is called spatting or setting
and the young oyster is called spat or
seed oyster.
Spa
t

8. CRITERION FOR SITE SELECTION
 Wave/wind action
 Salinity
 Oysters thrive best in brackish- and full strength seawater.
 Optimum range is about 17—26 ppt
 Natural food supply
 Availability of broodstock/seeds
 Pollution
 Water depth

9. SEED COLLECTION FROM WILD
 natural spat collection or through hatchery rearing
 For collection of spat from natural grounds, suitable spat collectors or
cultch materials are provided at appropriate time which may be oyster
shells, coconut shells, asbestos sheets, mussel shells or other materials.
 The choice of spat collectors depends on the culture method adopted,
materials availability, economical and practical considerations.
 The spat collectors should be rough, free from slime, without any
secretion of resins and strong to retain the oysters.
 Lime coated tiles and oyster shell are suitable for large scale spat
collection.
 The tiles are arranged in trays and are placed on racks, where as oyster
shell are arranged on a nylon rope of 1.50m,length,as strings and placed on
racks.

11. SEED COLLECTION THROUGH
HATCHERY
Selection and holding of broodstock
Oysters of length ranging from 60-90 mm are ideal and30% of them
should be 60-75 mm in order to have assured availability of males.
oysters are selected, cleaned and placed on synthetic twine on a PVC
frame in a 100L fiberglass tank and precooled
seawater (at 20C – 22C) is filled in the tank and aerated Mixed algae
with cell concentration of 1.5-2 million cells/ml is given as food
daily.

12. Induced spawning:
 Chemical stimulation: Injections of hydrogen peroxide, serotonin,
and sex steroids into the gonad or mantel of the broodstock
 Physical shock: Rapid changes in water temperature or salinity, the
addition of microalgae, and mimicking tidal patterns
 Biological stimulation: Changes in the phytoplankton biomass

13. Life cycle of edible
oyster

14. • About 20 hours after fertilization, the trochophore larva that hatches out
develops into veliger larva. It is a free swimming larva.
• The veliger larva is to be stocked at the rate of two numbers per ml of
water in the FRP tanks.
• On day one, no feeding is required. The rearing tanks are usually covered
with thick black cloth to avoid dust and light.
• On day two, micro algae, Isochrysis galbana @ 5000 cells/larva/day is to
fed to the larvae. Water is exchanged once in two days using 45 μm
sieve. This is continued till 10th day.
• Between 10th and 12th day, veliger reaches umbo stage. At this time
feeding is doubled and 80 μm sieve is used for water exchange.
• On 15th day, umbo stage reaches eyespot stage. At this time water
exchange can be with 100 μm sieve.
Larval rearing:

15. • On the day 18th, when pediveliger stages is reached feeding has to be 15000
cells/larva/day.
• On day 20th, Plantigrade stage is reached when water exchange is done using
140 μm sieve.
• On day 24 Plantigrade transforms into spat when Isochrysis @ 20000
cells/spat/day is given up to 30th day.
• Water exchange is done using180 μm sieve. Spat will settle to the sides and
bottom of the rearing tank.
• Feeding is increased to 30000 cells/spat./day and aeration is also done. By 45th
day spat grows to 1000 μm and feeding dose is increased thereafter to 50000
cells/spat /day up to 60th day.
• At this time mixed algae cultured out doors containing Chaetoceros is mixed
with Isochrysis is given at the ratio 50:50.
• Chaetoceros is considered good for the spat.
• It grows to 2-3 mm size and at this stage Isochrysis feeding is stopped and only
mixed algae is given.
• By 90th day spat becomes 3-5 mm. It is transferred to farm for further culture.

16. GROW OUT- CULTURE
The Grow out culture technique is broadly divided into
1) on-bottom :In the on-bottom culture, the seed
oysters are grown on the ground. This method is
substrata-specific and the area should be free from
silting and predators.
2)off-bottom culture: Off-bottom methods, the
advantages lie in better growth and good condition of
the meat. The methods involved in off-bottom culture
are
(1) rack & tray,
(2) rack & string,
(3) stake
(4)raft
(5)Iong-line method

17. Rack &
string,
Rack &
tray
Stake
culture
Raft
culture
Iong-line method

18. HARVESTING
 Oysters reach harvestable size (above 80 mm)within 10-12
months
 They are harvested when the condition of meat reaches high
value.
 Harvesting is done manually
DEPURATION
During depuration the shellfish are placed in cleaning tanks under
a flow of filtered seawater.
In this system 10-20% of the seawater is continuously replaced in
the tanks and the oysters are held for 24hours.
As a result the bacterial load of the shellfish is reduced.
During depuration at the end of 12 hours the water in the tank is
drained and the oysters are cleaned by hosing a strong jet of water
to remove the accumulated faeces.
Again the tanks are filled with filtered seawater and the flow is
maintained for another 12 hours.
At the end of this period, the tanks are drained again and flushed
by hosing water.
Finally the oysters are held for one hour in 3 ppm chlorine
seawater.
Then the oysters are washed once more in filtered seawater and
kept ready for marketing.

19. PEARL OYSTER
The world's main pearling grounds were depleted in the 18th century
due to constant demand
By the beginning of the twentieth century most of the world's pearl-
producing mollusks were in immediate danger of extinction
Pearls are made of NACRE
 A natural substance produced by mollusks that also costs the inside of the animal's
shell (also called "mother of pearl")
Nacre is made up mostly of calcium carbonate in the form of the
mineral aragonite and held together by crystal layers called conchiolin
They are not "inorganic“ as most stones are but "organic“
Pearl oysters are extensively farmed by Japanese for production of
pearl.

20. Kokichi Mikimoto, in 1893 created the world's first culture pearl by
manually introducing an irritant into an oyster to stimulate it to form a
pearl.
Tokishi Nishikawa and Tatsuhei Mise independently learned the secret
to spherical pearl production. Their discovery is commonly known as
the "Mise-Nishikawa method".
In India, in October 1972, the CMFRI started a pearl culture research
project at Tuticorin. Success came in July 1973 when a perfectly
spherical pearl was produced.

21. MAJOR PEARL
OYSTER SPECIES
Pinctada fucata (Gould)
Pinctada margaritifera
(Linnaeus)
Pinctada chemnitzii (Philippi)
Pinctada sugillata (Reeve)
Pinctada anomioides (Reeve)
Pinctada atropurpurea (Dunker)
TAXONOMY
Kingdom: Animalia
Phylum: Mollusca
Class: Bivalvia
Order: Pterioida
Family: Pteriidae
Genus: Pinctada

22. DISTRIBUTION
Pearl oysters of the genus Pinctada are widely distributed in the
world.
They occur in several seas of the tropical belt and in the sub-tropical
region.
number of species of pearl oysters have been identified, only a few
have been found to produce pearls of good quality and commercial
value. Of these, P.maxima, P.margaritifera and P.fucata stand out.
The gold/silver-lip pearl oyster P. maxima occurs along the north
coast of Australia, Burma, Thailand, Indonesia, Philippines and
Papua New Guinea at depths ranging from low tide level to 80 m.
In the Indian waters six species of pearl oysters occur but only P.
fucata has contributed to the pearl fisheries in the Gulf of Mannar and
Gulf of Kutch.
In the Gulf of Mannar, the pearl oysters occur in large numbers on the
submerged rocky or hard substrata known as paars.

23. REPRODUCTIVE BIOLOGY
Reproduction In pearl oysters, the
sexes are separate although
hermaphrodite conditions have been
observed in some individuals.
Change of sex takes place in some
oyster towards the end of spawning.
Based on the external appearance,
microscopic examination of smears
and histological studies, five
developmental stage shave been
distinguished in the gonads of P. fucata
off Tuticorin coast.

24. CRITERION FOR SITE SELECTION
 Wave/wind action
 Salinity
 Oysters thrive best in brackish- and full strength seawater.
 Optimum range is about 17—26 ppt
 Natural food supply
 Availability of broodstock/seeds
 Pollution
 Water depth
 Red tide, hydrogen sulphide, domestic
effluent etc type of hazards are unsuitable

25. Bottom
Gravelly bottoms are suitable for pearl
oyster farming,
while sandy or muddy bottoms should
be avoided.
The chemical and physical state of the
sea bottom is affected by the organic
substances discharged from the
oysters and fouling organisms.
Periodic removal of such accumulated
substances from the bottom of the
culture grounds often increase
production as well as quality.
Temperature
In temperate regions, the water temperature
plays an important role in the biological
activities of pearl oysters.
In Japan, the optimum temperature for
oyster growth has been found to be between
20—25C.
A temperature below 13C causes
hibernation .
Below 6 0 C, the oysters die.
At temperatures above 28C, the oysters
show exhaustion.
The thickness of the pearl layers are affected
by the minute changes in water temperature
during the day and also vary considerably
according to the season of the year.
Salinity
Pearl oysters tolerate a wide range of salinity.
it appears that pearl oysters tend to prefer high salinities. Oysters raised in such salinities
produce pearls with a golden tint.

26. HATCHERY TECHNOLOGY
In order to produce the seed of pearl oyster (spat stage) the following
are required:
1) Brood stock development unit
2) Induced spawning unit
3) Larval rearing unit
4) Algal culture unit
Same as edible oyster breeding

27. ALGAL CULTURE UNIT
Isochrysis is the microalgae required for feeding the
larval stage up to 60th day of rearing. Hence, facilities
are to be made for its mass culture and also for mixed
algal culture as mixed algae is given as feed during the
later stages.

28. THANK YOU